[RFC PATCH 13/15] pwm: rockchip: add support for atomic update

Boris Brezillon
2015-07-02T07:43:19Z

Hi Heiko,

On Wed, 01 Jul 2015 23:48:31 +0200
Heiko St?bner <heiko@sntech.de> wrote:

> Hi Boris,
>
>
> Am Mittwoch, 1. Juli 2015, 10:21:59 schrieb Boris Brezillon:
> > Implement the ->apply() function to add support for atomic update.
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> > ---
> > @@ -110,6 +113,26 @@ static void rockchip_pwm_set_enable_v2(struct pwm_chip
> > *chip, writel_relaxed(val, pc->base + pc->data->regs.ctrl);
> > }
> >
> > +static void rockchip_pwm_init_v2(struct pwm_chip *chip, struct pwm_device
> > *pwm) +{
> > + struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
> > + u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
> > + PWM_CONTINUOUS;
> > + u32 val;
> > +
> > + val = readl(pc->base + pc->data->regs.ctrl);
> > +
> > + if ((val & enable_conf) != enable_conf)
> > + return;
> > +
> > + pwm->state.enabled = true;
> > +
> > + enable_conf = PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
> > +
> > + if ((val & enable_conf) == enable_conf)
> > + pwm->state.polarity = PWM_POLARITY_INVERSED;
>
> the inactive setting does not affect the polarity of the running pwm, only what
> to do when it gets turned off. Also PWM_DUTY_NEGATIVE is the "0" value for the
> bit so also is bad to compare against (and results in wrong readings). So I
> would suggest changing this like

Indeed

>
> - enable_conf = PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
> + enable_conf = PWM_DUTY_POSITIVE;
>
> - if ((val & enable_conf) == enable_conf)
> + if ((val & enable_conf) != enable_conf)

Or just:

if(val & PWM_DUTY_POSITIVE)

Thanks for the fix.

Best Regards,

Boris

--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering